1. Field of Invention
The present invention relates to thin-film semiconductor devices and methods of manufacturing the same. More specifically, the invention relates to a thin-film semiconductor device, including a thin film which has been formed into a predetermined pattern, and a method of manufacturing the same. Also, the present invention relates to an electro-optical device including such a thin-film semiconductor device, and to a method of manufacturing the same. In addition, the present invention relates to a reticle suitable for use in manufacturing the thin-film semiconductor device and the electro-optical device.
2. Description of Related Art
In the related art, photolithography can be used to form thin-film semiconductor devices. Photolithography is a technique of forming wiring lines, circuit elements, or the like, having a desired pattern, on the surface of a substrate. More particularly, firstly, a thin film composed of, for example, silicon, and subsequently a resist film are formed on the entire surface of the substrate (a film forming step), and then exposure with a predetermined pattern is performed on the resist film (an exposing step). In the related art, the exposure with a predetermined pattern is achieved by a method in which light emitted from a light source is projected onto the resist film via a reticle having the predetermined pattern. With this exposure, the resist film has photosensitive regions and photo-insensitive regions formed therein in accordance with the predetermined pattern.
Then, the resist film is developed and the resist film in the photosensitive region is removed (a developing step). Subsequently, after baking the remaining resist film, by etching a part of the thin film from which the resist film has been removed and which is exposed (an etching step), the thin film is provided with the predetermined pattern, that is, the thin film is formed so as to have predetermined wiring lines and circuit elements (hereinafter the thin film formed as described above is referred to as a “patterned film”).
When a thin film, such as an insulating film, is further laminated on the patterned film having the predetermined pattern, sometimes a cleaning step, such as a light etching process using a diluted hydrofluoric acid solution, is conducted in order to clean the surface of the patterned film.
Since wiring lines and circuit elements having various fine patterns can be easily and reliably formed with such a photolithographic technology, in the related art it can be viewed as an essential manufacturing technology in the semiconductor industry. A technique that uses such a photolithographic technology to form liquid crystal devices is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 6-258667 (hereinafter “JP 6-258667).